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; Name:         CreateTemporaryFileName
; Synopsis:     filename = CreateTemporaryFileName(prefix)
; Parameters:   prefix.s - The prefix to be applied to the temporary filename
; Returns:      filename.s - A filename in the temporary directory, with a temporary name
; Globals:      None
; Description:  Creates a filename for a temporary file, which will be in the format of
;               <temp_dir>\<prefix><uuuu>.TMP where temp_dir is the temporary directory (see
;               below), prefix is up to 3 characters from the passed prefix string and
;               uuuu is a unique identifier generated by the OS.
;
;               <temp_dir> calculation (taken from MSDN docs for GetTempPath
;                   The GetTempPath function does not verify that the directory specified by the TMP Or TEMP environment variables exists. The function gets the temporary file path as follows:
;                       The path specified by the TMP environment variable. 
;                       The path specified by the TEMP environment variable, If TMP is not defined. 
;                       The Windows directory, If both TMP And TEMP are not defined. 
;                   Windows Me/98/95:  The GetTempPath function gets the temporary file path as follows:
;                       The path specified by the TMP environment variable. 
;                       The path specified by the TEMP environment variable, If TMP is not defined Or If TMP specifies a directory that does not exist. 
;                       The current directory, If both TMP And TEMP are not defined Or specify nonexistent directories. 
Procedure.s CreateTemporaryFileName(prefix.s)
    DefType.s   filename
    
    DefType.l   temp_path_length            ; Length of the string in the temporary path
    Dim         temp_path.w(0)              ; Array of words (string of TCHARs) to hold the temporary pathname, if required
    Dim         temp_file.w(MAX_PATH + 1)   ; Array of words (string of TCHARs) to hold the temporary filename, if required
    Dim         prefix_oem.w(4)             ; TCHAR string for the prefix string if any
    
    ; Set return filename to empty (to indicate failure of some sort)
    filename = ""
    
    ; Get required length of temporary directory
    temp_path_length = GetTempPath_(0, @temp_path(0)) - 1   ; GTP_() includes terminating NULL, remove that
    If temp_path_length And temp_path_length <= (#MAX_PATH-14)
    
        ; Create TCHAR string for the number of characters required + NULL and get string
        Dim temp_path.w(temp_path_length + 1)
        If temp_path_length = GetTempPath_(temp_path_length + 1, @temp_path(0))

            ; Try to create the prefix 3 characters
            OemToCharBuff_(@prefix, @prefix_oem(0), 3)
            
            ; Get temporary filename in entirety
            If GetTempFileName_(@temp_path(0), @prefix_oem(0), 0, @temp_file(0))
                ; Convert TCHAR string to ASCII, for use with PB
                filename = Space(temp_path_length)
                If CharToOem_(@temp_file(0), @filename)=0
                    filename = ""
                EndIf ; Failed to convert the TCHAR string to ASCII
            EndIf ; Created a temporary filename
        EndIf ; Temporary path copied successfully
    EndIf ; Temporary path had a valid length

    ProcedureReturn filename
EndProcedure

tfn.s = CreateTemporaryFileName("foo")
If tfn<>"" And CreateFile(0, tfn)
    WriteStringN("Hello, I am a temporary file")
    CloseFile(0)
Else
    MessageRequester("Gack!", "Could not create temporary file", #PB_MessageRequester_OK)
EndIf
End

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Procedure.s CreateTempFile()
  tmpdir$=Space(255) : GetTempPath_(255,tmpdir$)
  Repeat : file$=tmpdir$+Str(Random(99999999)) : Until FileSize(file$)=-1
  ProcedureReturn file$
EndProcedure

tfn$=CreateTempFile()
If tfn$<>"" And CreateFile(0,tfn$)
  WriteStringN("Hello, I am a temporary file")
  CloseFile(0)
Else
  MessageRequester("Gack!", "Could not create temporary file", #PB_MessageRequester_OK)
EndIf 

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  tmpdir$=Space(#Max_Path) : GetTempPath_(#Max_Path,tmpdir$)

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Procedure.s CreateTempFile(); - Return an name for temporary files (the file is created and closed!)
  temp$=Space(#MAX_PATH)
  tmpdir$=Space(#MAX_PATH) : GetTempPath_(#MAX_PATH,tmpdir$)
  If GetTempFileName_(@tmpdir$,@"~PB",0,@temp$)=0
    temp$=""
  EndIf
  ProcedureReturn temp$
EndProcedure

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TCHAR in Microsoft Windows
For programmers that have used the variety of string handling functions on the Microsoft Windows platform this character abstraction technique should look familar. It is indeed the same. The abstract character type in the Win32 environment is named TCHAR in uppercase rather than lower and the string functions are prefixed with _tcs like _tcsncpy rather than tcsncpy but after macro processing the resulting code is the same. The identifier names where chosen to be the same as those found on Windows (minus a few Windows coding conventions that clash with Unix/Linux conventions) simply becuase the Windows platform is very popular and there was no practical reason to use different names. The exception is that USE_WCHAR is used to signal that wide characters should be used rather than _UNICODE because on Unix and Unix-like systems multi-byte strings support Unicode in the UTF-8 locale which would make the _UNICODE macro somewhat inaccurate.